Oracle: Unbreak my Linux Heart

Howto convert a LiveCD image to a PXE Boot image . To convert the root of the ISO image to an NFS root and save on the RAM requirements when booting the image [RAM=2x(size of ISO in MB) + 60 MB], read this on PXE booting in general .

Where I had great difficulties trying to get OMSA to install let alone work in Oracle's Enterprise Linux 4 (u5 and above), I am happy to report that I got it working out-of-the-box after an install of my custom 5u3 image, following the instructions on the OMSA Repository Wiki . A simple http proxy setting, the wget boot strap line to configure yum and the dependencies and I was in business! Excellent work, Dell!

func is a system management layer to remotely manage a whole set of systems. A bit of ssh, WBEM, keys and command lines. Check out their site! I may just give this a try...

Cobbler is a Linux installation server that allows for rapid setup of network installation environments. With a simple series of commands, network installs can be configured for PXE, reinstallations, media-based net-installs, and virtualized installs (supporting Xen, qemu, KVM, and VMware Server). Cobbler uses a helper program called 'koan' (which interacts with Cobbler) for reinstallation and virtualization support. Cobbler can also optionally help with managing DHCP, DNS, and yum package mirroring infrastructure -- in this regard, it is a more generalized "provisioning" server, rather than just dealing specifically with installations. It has a command line interface, a web interface, and also several API access options. That sounds like a lot, but it's really pretty simple.

A discussion on the Dell poweredge mailing list on a Dell Warranty check , resulted in a small tidbit to discover the Dell service tag from the Linux command line. :) Using dmidecode | grep -i serial , with or without using sudo or changing to root, you get the service tag of your bare metal Linux server. Using this service tag, you can query Dell support to find out if you still have a warranty.

While researching ways to create a custom boot image , so I can provision new systems automatically with a CD or a mounted ISO image, I also learned how to create a custom splash.lss image . Most web pages out there instruct you to install ancient, obscure giftoppm tools - which you may not have or know how to get. I found out Irfanview (for Windows) easily lets you open and edit JPG or GIF images, rework them, add logos and text and save the result as a PPM file. Then just scp the .ppm file to Linux and use the ppmtolss16 tool (obtained through 'yum install syslinux') to convert the PPM file to LSS. Build the custom ISO image and you're done!

A semi-random Google browse landed me on the Official Oracle Wiki, where I found a Linux installation kickstart for Oracle database . It's a sample kickstart file for a local disk installation using the minimum packages needed by Oracle software (i.e. the database, application server, etc.). The script also sets runlevels for daemon and deinstalls all that is not needed, as well as kernel parameters. It's interesting to see their list because I highly optimizes the packages list compared to what we have. But the list of parameters, default daemons to run and in which runlevel is very close to what we arrived at by experimenting lots. :)

Funny, I was searching for this last Summer but couldn't find a good way then. Now, I found instructions on Red Hat for forcing a Linux user to change his password on first login ! It's easy too and along the lines I was thinking then, but simply couldn't put together. Create the user, set a password, lock the account, use chage and unlock the account...

Found a good site that explains the mrepo configuration on setting up an apt/yum repository from ISO images, online updates, patches and custom packages... Looks to be very cool and much more flexible than Oracle's own ULN local mirror function...

Just thought I'd mention this as this is the first time I ran into this... On Oracle Linux, just as on Fedora, CentOS and Red Hat, you usually install software using either up2date (blah) or yum (much better). However, setting up a local mirror for network installs or local updates, is somewhat daunting. Especially when used to the comfortable ease of Debian-based distos as they have all sources available for free on the net. Therefore it nice to know that some dedicated fellows like Dag Wieers use their time to make life a little easier for you. With tools like mrepo: yum/apt repository mirroring (formerly known as 'yam'). I haven't played with this yet, but I'm gonna look into it for sure!

$#%@&%#@$!!! I was having an issue with existing local user accounts on my NIS test server. As indicated in /etc/nssswitch.conf , local files override NIS settings. So starting with a clean system - as far as user accounts go - is a great idea. However, I was also using the local system group wheel for daily management purposes. So it goes without saying that I was confused as to why my own account did not get wheel permissions on my test server. Doing an " id myuserid " on the NIS server showed uid=500(myuserid) gid=100(users) groups=10(wheel),100(users) , while the same command on my NIS test server showed uid=500(myuserid) gid=100(users) groups=100(users) . What gives? Well, there is a file called /var/yp/Makefile that lists which UIDs and GIDs will be transmitted i.e. synced over NIS. Default is 500. So any user account and group below that will not get replicated. *sigh* I did read that while installing but forget when testing. An old Pipermail archive pointed th...

I got NIS working last week, but simply following HOWTO guide from Linux Home Networking. Thanks guys! Only difference was that I explicitly defined /etc/securenets and did not need to set the NIS_DOMAIN_NAME as the server opted, but used my existing domain name instead. So instead of setting /etc/sysconfig/network to contain something like NIS_DOMAIN_NAME=MY-NIS-STUFF , I used the same name as my subdomain, i.e. NIS_DOMAIN_NAME=sub.domain.tld . After that, I started the NFS auto mounter on the clients, ran authconfig to set authentication to NIS (don't enable shadow passwords over NIS!) All that remains to be done, is testing, testing and testing, securing NIS for now, setting up a good, solid sudoers file and try to get Oracle's OEM working with NIS... (Hint: test or debug sudo with sudo -l ) Update: do yourself a favor and userdel and groupdel all local accounts or groups (except root) on your to-be NIS client(s), or at least prevent a NIS user from having the same nam...

After political and time pressure not to pursue any commercial products to integrate Linux user authentication into MS AD, I'm falling back to my original plan to set-up NIS(+) for now and deal with AD later... I followed instructions at Linux Home Networking and got the NFS server running but would get an error when logging in as a user: "unable to chdir to home directory". Fortunately, it seems a common error when using NIS and NFS (and Kerberos). It turns out my NFS client wasn't correctly configured. The automount file /etc/auto.home for /home listed my subnetwork (10.X.0.0/16). That's what I had the NFS server configured for. The automount file should just list '*' there... Next is NIS...

We've been having a variety of problems with our LVM system partitioning and anaconda. Mind you, once it is configured and installed, the system runs fine. But during rollout, LVM has been a head breaker... Main issue is: dirty disks. Since we are booting from SAN, we have no control over the LUNs we get. Although we specify zerombr and clearpart --all in anaconda, LVM complains if there is anything on the disk. Especially if there are non-Linux partitions left on the disks. Altiris does it's boot "magic" using a DOS partition to create a known environment from which it launches stuff. This gave the anaconda installer headaches. Our work-around: don't do partitioning from anaconda, but use the pre-install phase (%pre). We force a clear of the local disk (sda) and our boot LUN (sdb) and clear partitions explicitly as well as remove any traces of LVM signatures. We remove all Logical Volumes (LV), Volume Groups (VG) and Physical Volumes (PV). While this is a lo...

We're using Oracle Enterprise Manager (OEM) to monitor and control all of our Oracle Linux servers. I know, Cacti , Zabbix or OpenQRM or any SNMP-based tool could also do the trick. But OEM comes integrated very well with alerts and triggers for the RDBMS, as well as the Linux platform. So it's less work to get up and running. Thus we need the OEM agent to be installed on all machines. Download the latest agent that matches your platform from Oracle's website. Careful! The Management Agent varies between 250 MB and 1000 MB in size, depending on your version and platform! Use a fast connection and a proper download manager like wget .

Been looking some more into the user administration issues I face when maintaining a few hunderd Linux servers for various people, customers and developers... Centrify seems to have a nice product that allows me to authenticate Linux users against an (existing) MS Active Directory Server (AD). While that is nice, it is not enough. Granted, their DirectControl family of products covers a lot and is nice, what I miss is the ability to control which user can issue what commands on a Linux/Unix level. That is, DirectControl does not seem to link into the su/sudo/sudoers facilities of Linux. NIS is a common way to centralize Linux user management on a network and control access to servers, do password management and so on. However, I thought NIS was largely incompatible with more common, cross-platform directory solutions such as LDAP. Even MS AD can talk LDAP! ;) So I was more than happy to discover that PADL provides free toosl to help migrate from flat access files (passwd, NIS, etc.) ...

Finally got the scripted network install working as expected. Here is how... Dell BIOS is at 1.3.7 Qlogic BIOS is at 1.24, BIOS enabled, boot LUN assigned. I disabled the 2nd HBA so the server only has one path to the SAN. Mount the Oracle Linux CD1 through Dell's DRAC interface and (re)boot the machine. Typ " linux ks=http://10.1.1.1/oel/ks.cfg ksdevice=eth0 " to start the installation and load your script. Your kickstart script should be located in the root of your installation sources, i.e. where you stored the contents of all the CDs. The last parameters is needed in case your server has multiple NICs, like ours, and avoid being asked which network card you want to use for installation. Since DHCP is enabled on that subnet, that's all that is needed. Now there is one more tricky part... upon loading the kickstart script, before the installation can start, you MUST disconnect the CD image that is still mounted in DRAC. If not, you get an endless loop and installati...

When using kickstart and a network install to do unattended installations of Oracle Linux, you mahttp://www.blogger.com/img/gl.link.gify need to reference the Kickstart Options . In my case, when trying to provision Linux servers that boot from SAN, the kickstart file that is automatically created for you after a manual install ( /root/anaconda-ks.cfg ), did not contain all the options I had given it. Specifically, your boot device must come first in the drive order. Here, sda is the local disk from the Dell PERC controller, sdb is the first LUN on the SAN. The bootloader option must therefore get the right parameter --driveorder=sdb,sda .

If you do an installation of a Linux server over the network (called a "network install"), you'll save yourself a lot of time: you don't need to change CDs. You can also automate installation with a so-called "scripted install" using a kickstart file. This will get you an "unattended installation". A sample file anaconda-ks.cfg is saved in /root at the end of every manual install. You can use that as a starting point to create your own. When doing a network installation of Linux, you can tell Linux to use the kickstart file using a range of options . Please check the Red Hat docs for your favorite options. How do you do a network installation when booting from a CD (or PXE server)? Simple! Insert CD 1, or mount that image through DRAC or iLO, at boot the machine. At the first command line of the boot CD type: linux ks=http://server/path/kickstart_file.cfg url=http://server/path For instance, linux ks=ftp://myserver/default-ks.cfg url=ftp://myserv...

I tried to image our Linux servers, taking a "golden image" from one of our bare metal servers. I wanted to have a quick restore available in case I seriously cripple a serever during testing. In earlier runs, the restore worked but the Linux image had become unusable. GRUB wouldn't produce anything beyond its first 4 letters, so I created another server and imaged that. Same thing... Turns out I am using a Dell Poweredge 2950 with a local disk in RAID1 (mirror). I only use the local disk as swap area, creating a big LVM Volume Group (VG) on it called VGinternal. The actual boot disk is a LUN on the SAN. It also uses LVM and I have a VG in the LUN called VGsystem. VGsystem holds the actual system partitions /, /var and /tmp. When Altiris images this, it uses raw mode to capture the LVM partitions. Upon deploying the image containing LVM disk info, you must tell the DS to use the Linux environment . Not the WinPE or DOS modes... Testing it later...